Avidity and subtyping of specific antibodies applied to the indirect assessment of heterologous protection against Foot-and-Mouth Disease Virus in cattle

► Avidity and subtypes were studied in 64 bovine sera from vaccine matching trials. ► The tests discriminated between protected and not protected animals against the heterologous challenge. ► High avidity antibodies to the heterologous strain were related to cross-protection. ► Protected cattle with low neutralizing antibodies had higher IgG1 than IgG2 titers. ► These tests may complement current vaccine-matching serological assessments.